聚丙烯/聚乙二醇改性蒙脱土纳米复合材料的力学和流变性能

通过熔融插层法制备了聚丙烯/蒙脱土(PP/MMT)纳米复合材料。利用X射线衍射(XRD)和透射电镜表征了PP/MMT纳米复合材料的插层结构。XRD结果表明,经过聚乙二醇(PEG)处理的蒙脱土层间距增大;透射电镜(TEM)照片显示,蒙脱土在PP基体中达到纳米级分散,且分散均匀。PP/MMT纳米复合材料力学性能得到较大提高。加入5份改性MMT时,复合材料的缺口冲击强度和断裂伸长率分别从纯PP的3.93kJ/m2、74.46%提高到9.95kJ/m2、220.66%。动态流变性能测试结果表明,MMT的加入降低了PP的复数黏度(η*)、储能模量(G′)和耗能模量(G″)。     

聚丙烯(PP)/纳米二氧化硅SiO2复合材料的制备及其性能研究

纳米材料因其独特的性能而广泛应用于聚丙烯(PP)等高分子材料的改性.本文用纳米二氧化硅与PP共混进行改性,利用双螺杆共混方法制备聚丙烯(PP)/纳米二氧化硅(SiO2)复合材料,研究了聚丙烯(PP)/纳米二氧化硅(SiO2)复合材料的力学性能,采用熔融流变仪、XRD、SEM对熔体流动速率、PP物相情况等进行了研究.实验结果表明,2%含量的纳米二氧化硅聚丙烯纳米复合材料综合性能最佳,提高了PP的综合力学性能.在本文中对纳米SiO2改性PP的机理进行了初步探讨,利用X射线衍射图谱分析,结果表明纳米SiO2的加入对PP中β晶型的产生有诱导作用.     

纳米有机蛭石/ 天然橡胶复合材料的制备及性能

以十六烷基三甲基溴化铵为插层剂, 用球磨法对蛭石进行了快速有机插层, 用过熔融共混法制备出纳米有机蛭石/ 天然橡胶复合材料。用XRD、SEM、TEM 对其微观结构进行了表征与分析, 证明蛭石以纳米片层分散在天然橡胶基体中。力学性能测试表明: 复合材料拉伸强度、扯断伸长率、300 %定伸强度、邵氏A 硬度、撕裂强度得到明显的改善。DMA、DSC 测试表明: 复合材料的模量具有明显的提高, 而玻璃化转变温度无明显变化。可见有机插层蛭石对天然橡胶的综合性能具有较明显的改善作用。      

聚丙烯/四钛酸钾晶须复合材料研究

以PP-g-GMA为增容剂,利用熔融共混法制备了PP/PP-g-GMA/K_2Ti_4O_9晶须复合材料,借助于SEM、DSC和其他测试手段对复合材料的结构和性能进行了考查.SEM观察发现,K_2Ti_4O_9晶须含量较低时,分散较均匀,与树脂界面结合较好,含量较高时,粒子有团聚现象.力学性能测试结果表明,K_2Ti_4O_9晶须的加入提高了基体树脂的缺口冲击强度,对材料的拉伸强度影响不大.DSC测试结果表明,K_2Ti_4O_9晶须对PP的结晶有异相成核作用,出现双熔融峰和双结晶峰现象,使PP的结晶度提高,同时使PP的结晶温度大幅提高.     

SEBS、纳米SiO2协同作用改性PP的研究

采用熔融共混的方法制备出PP/SEBS/纳米SiO2复合材料,通过对复合材料进行SEM、DSC、偏光显微镜以及力学性能等测试,研究了纳米SiO2含量对复合材料的结构与性能的影响。研究表明纳米SiO2可以促进SEBS在PP基体中均匀分布,且随着复合材料中纳米SiO2含量的增加复合材料的球晶尺寸减小、晶粒细化、结晶度降低,冲击强度尤其是低温冲击强度有很大改善而拉伸强度降低不大。     

AA改性纳米CaCO3/聚丙烯的力学性能

用熔融挤出法制备了丙烯酸(AA)改性纳米CaCO3／PP母料及复合材料，系统研究了两种粒径的纳米CaCO3、单体AA和引发剂DCP的用量，以及制备母料的不同基体对纳米CaCO3／PP复合材料力学性能的影响。结果表明纳米CaCO3／PP复合材料的力学性能高于微米CaCO3／PP复合材料，纳米CaCO3对PP有增强增韧作用。在制备母料过程中加入AA，有助于进一步提高纳米CaCO3／PP复合材料的力学性能。加入少量DCP也有利于提高复合材料的力学性能。制备母料的基体为粉状PP的力学性能高于粒状PP。     

聚丙烯/有机蒙脱土纳米复合材料的制备及性能

以马来酸酐接枝低分子量的聚丙烯(M APP)为相容剂,采用熔融插层法,制备了聚丙烯(PP)/有机蒙脱土(OMM T)纳米复合材料;采用微机控制电子万能试验机、悬臂梁冲击试验机研究了复合材料的力学性能;采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和偏光显微镜(POM)等对复合材料的微观结构进行了研究。结果表明,熔融插层法能够获得较好的插层效果,适量蒙脱土的加入使聚丙烯的球晶数量增多,球晶尺寸变小;复合材料的拉伸强度和冲击强度都是先增加后降低,总体上来说,拉伸强度高于纯聚丙烯,冲击强度与纯聚丙烯相近。     

原位插层聚合法制备聚苯乙烯/海泡石纳米复合材料

采用十八烷基三甲基氯化铵(OTAC)作为有机插层剂对海泡石进行了有机化处理,该有机化的海泡石粒子在苯乙烯单体中很容易地均匀分散并形成稳定的胶体溶液.通过对分散有海泡石的苯乙烯进行原位插层聚合制备了聚苯乙烯/海泡石纳米复合材料.并用X射线衍射(XRD)、傅里叶变换红外光谱(FT-IR)、扫描电镜(SEM)和透射电镜(TEM)对聚苯乙烯/海泡石复合材料的结构进行了表征.研究表明聚苯乙烯的大分子链插入到海泡石片层间,形成了部分插层、部分剥离型纳米复合材料.     

水滑石及相容剂对聚丙烯结晶性能的影响

通过熔融插层法制备了三种聚丙烯/水滑石(PP/LDHs)纳米复合材料。采用透射电镜(TEM)、X射线衍射仪(XRD)和差示扫描量热仪(DSC)研究了水滑石(LDHs)和相容剂PP-g-(MAH-co-St)对聚丙烯结晶性能的影响,以及水滑石在基体中的分散情况。结果表明,改性水滑石在基体中片层发生剥离,提高了聚丙烯的起始结晶温度、结晶速率,减小了聚丙烯晶粒的110、010晶面尺寸;相容剂PP-g-(MAH-co-St)使聚丙烯的结晶速率降低,晶粒粒径分布变宽,同时减弱了改性水滑石对聚丙烯晶粒晶面尺寸的影响。     

原位乳液插层法制备PBA/OMMT纳米复合母料及其在ABS中的应用

通过原位乳液插层法制备高有机蒙脱土(OMMT)含量的聚丙烯酸丁酯/有机蒙脱土(PBA/0MMT)纳米复合物,将其作为母料与ABS进一步熔融插层制得力学性能良好的ABS/OMMT纳米复合材料,并通过XRD、TGA和TEM等对材料进行了表征.结果表明:制得的PBA/OMMT母料为插层型纳米复合物,OMMT片层间距从2.38nm增大到3.85nm;采用母料法制备ABS/OMMT纳米复合材料,ABS链段易插层进入OMMT层间,使OMMT片层在ABS基体中达到剥离并以纳米尺度均匀分散,较好地保持了ABS的缺口冲击强度.     

天然橡胶/固相改性蒙脱土纳米复合材料的制备与表征

在固相对蒙脱土进行有机改性,并与天然橡胶机械混炼插层制备了纳米复合材料。利用X射线衍射仪(XRD)、橡胶加工分析仪(RPA)和透射电镜(TEM)等研究了天然橡胶/固相改性蒙脱土纳米复合材料的结构,同时考察了材料的力学性能和耐老化性能。结果表明:固相改性蒙脱土在天然橡胶中可以实现纳米级分散,得到天然橡胶/蒙脱土纳米复合材料。固相改性蒙脱土对天然橡胶不但具有明显的补强效果,大幅度提高材料的力学性能和耐热氧老化性能,而且还具有很好的促进硫化作用。     

Preparation,structure and thermal properties of polylactide/sepiolite nanocomposites with and without organic modifiers

Polylactide-based nanocomposites containing unmodified and organic modified sepiolite were prepared through a solution casting method. The structure and properties of materials were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). From the results it can be concluded that the bundles of sepiolite have been dispersed into small aggregates containing several nanorods without destroying the crystal structure. Sepiolite nanofibers were well dispersed in the PLA matrix, exhibiting a randomly orientation with the contact among them in all cases. But the thermal stability of nanocomposites has been improved more by introducing unmodified sepiolite than that with organic modified sepiolite, which has also been confirmed by molecular dynamics simulation results that hydrophobic parts of organic modifiers could prevent the interaction between PLA molecules and sepiolite surface.     

熔融插层法制备EPDM/OMMT纳米复合材料研究

采用熔融插层法,通过插层剂优选、配方设计与工艺优化,制备了密封用三元乙丙橡胶/有机蒙脱土(EPDM/OMMT)纳米复合材料,借助XRD分析了其微观结构,利用TG分析了其热稳定性,并初步研究了其气体阻隔性能与相关力学性能.结果表明,EPDM与OMMT经熔融插层形成插层型纳米复合材料,气体阻隔性能得到显著提高,相关力学性能也得以改善.     

The effect of multi-walled carbon nanotubes addition on the thermo-oxidative decomposition and flammability of PP/MWCNT nanocomposites

Studies of thermo-oxidative and fire-resistant properties of the polypropylene/multi-walled carbon nanotube composites (PP/MWCNT) prepared by melt intercalation are discussed. The effective kinetic parameters of the PP/MWCNT thermo-oxidative decomposition were computed according to the model-based kinetic analysis. The thermo-oxidative decomposition behavior of PP/MWCNT and stabilizing effect caused by addition of MWCNT has been investigated by means of TGA and EPR spectroscopy. Comparative analysis of the flammability characteristics for PP-clay/MWCNT nanocomposites was provided in order to emphasize the specific behavior of the nanocomposites.     

原位聚合制备不饱和聚酯树脂/高岭土纳米复合材料及性能表征

利用超声法制备了高岭土-DMSO插层复合物前驱体,采取二步取代,原位聚合制备了不饱和聚酯树脂/高岭土纳米复合材料,并用XRD、FT-IR等手段对材料结构进行了表征,研究了纳米复合材料的阻燃性能。结果表明:当DMSO分子插入到高岭土层间时,d(001)值由0.717 nm增大到1.12 nm,插层率为91%,而不饱和聚酯树脂取代DMSO进入高岭土层间后,表征层状结构的d(001)特征衍射峰完全消失,高岭土内表面羟基吸收特征峰(3651 cm-1)和DMSO两个甲基的对称和反对称伸缩振动的吸收特征峰消失。燃烧实验表明这种材料相比纯树脂具有更好的阻燃性能。     

Effect of material and processing parameters on mechanical properties of Polypropylene/Ethylene–Propylene–Diene–Monomer/clay nanocomposites

Polypropylene/Ethylene–Propylene–Diene–Monomer (PP/EPDM) blends are well known for having a combination of favourable mechanical properties. In this paper, addition of organoclay to PP/EPDM to make PP/EPDM nanocomposites with enhanced mechanical properties is studied. PP/EPDM/organoclay nanocomposites were prepared using a lab scale twin-screw extruder. Maleic anhydride grafted polypropylene (PP-g-MA) was used to enhance the intercalation/exfoliation process and to create good adhesion at the polymer/polymer and polymer/filler interfaces. Taguchi method was employed to deign the experiments and optimize material and processing parameters for optimized mechanical properties. Organoclay (NC) and compatibilizer content were selected as material parameters and the main processing variables were feeding rate and average shear rate (RPM). X-ray diffraction (XRD), Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) were used to study the microstructure of the nanocomposites samples. It was observed that NC content and shear rate in extruder improved the tensile strength and modulus. Another important result was the insignificant effect of NC content on impact strength while increasing shear rate first increased and then decreased the impact strength.     

Improving the mechanical properties of thermoplastic starch/poly(vinyl alcohol)/clay nanocomposites

Thermoplastic starch/poly(vinyl alcohol) (PVOH)/clay nanocomposites, exhibiting the intercalated and exfoliated structures, were prepared via melt extrusion method. The effects of clay cation, water, PVOH and clay contents on clay intercalation and mechanical properties of nanocomposites were investigated. The experiments were carried out according to the Taguchi experimental design method. Montmorillonite (MMT) with three types of cation or modifier (Na⁺, alkyl ammonium ion, and citric acid) was examined. The prepared nanocomposites with modified montmorillonite indicated a mechanical improvement in the properties in comparison with pristine MMT. It was also observed that increases in tensile strength and modulus would be attained for nanocomposite samples with 10%, 5% and 4% (by weight) of water, PVOH and clay loading, respectively. The clay intercalation was examined by X-ray diffraction (XRD) patterns. The chemical structure and morphology of the optimum sample was also probed by FTIR spectroscopy and transmission electron microscopy (TEM).     

Influence of clay incorporation on the physical properties of polyethylene/Brazilian clay nanocomposites

High density polyethylene/Brazilian clay nanocomposites were prepared by the melt intercalation technique. A montmorillonite sample from Boa Vista/PB, Northeast of Brazil, was organically modified with esthearildimethylammonium chloride (Praepagen WB) quaternary ammonium salt. The unmodified and modified clays with the quaternary ammonium salt were introduced in 1, 2, 3 and 5 wt% in a PE polymer matrix. The dispersion analysis and the interlayer distance of the clay particles were obtained by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The mechanical properties of tensile and the flammability of the nanocomposites were studied. In general, the mechanical properties of the systems presented superior values compared to the matrix. The systems showed a reduction on the burning rate, indicating that the flammability resistance of nanocomposites was improved.     

熔融挤出插层制备聚丙烯/蒙脱土纳米复合材料的探讨(Ⅰ)

通过双螺杆挤出机熔融挤出法制备出插层型聚丙烯/蒙脱土纳米复合材料。利用有机蒙脱土的预凝胶测试,复合材料的透射电子显微镜(TEM)观察,熔体流动指数测试(M I),力学性能测试,耐热性测试等方法进行了表征。结果表明,通过本方法制备的聚丙烯/蒙脱土复合材料是典型的插层型纳米复合材料。该复合材料在有机蒙脱土质量分数仅为4.0%时缺口冲击强度提高了103%,耐热性有所提高,而屈服强度、刚性基本不变,为研制PPR管等同时具有高韧性和高耐热性的聚丙烯产品开辟了一条崭新的途径。     

Morphology development and stability of polypropylene/organoclay nanocomposites

A series of polypropylene (PP)/organoclay nanocomposites with varied concentrations of clay, from 1 to 7 wt%, was successfully prepared via melt intercalation using a PP functionalized with maleic anhydride as compatibilizer. The morphology/property relationships of the nanocomposites were investigated by XRD, TGA and DSC analyses. Two distinct groups of composites, from a quasi-exfoliated to an intercalated/flocculated morphology, were identified. In particular, intercalated/flocculated morphologies were obtained for those composites with an organoclay concentration beyond the threshold (3 wt%), as evidenced by XRD analysis and confirmed by the increase of the glass transition temperature. This last effect was related to the confinement of polymer chains between the silicate layers, generating a reduction of the chain mobility. The variable increase of the thermal stability of the nanocomposites was also likely related to the different degree of exfoliation/intercalation of the samples. The toluene extraction of composites was used as a powerful methodology to distinguish between polymer phases differently interacting with the inorganic surface: composites having a semi-exfoliated structure were split into two fractions having a similar morphology. For those samples having the higher organoclay concentration and intercalated morphology, a toluene-residue fraction was obtained containing almost all the clay present in the pristine composite. Furthermore, in this case the morphological analysis of the residue fraction evidenced a collapse of the inorganic structure compared to that of the unextracted composite. A careful characterization of both soluble and residue fractions is reported and the results are discussed considering the interactions at the interface between the functionalized PP chains and silicate layers and their effects on the organoclay dispersion degree and stability.